The present invention relates to a device and a method for manufacturing at least one radial centering surface on an outer circumference of an annular laminated core of a stator for an electrical machine, an electrical machine manufactured according to this method, and a stator—manufactured according to this method—for an electrical machine.
With the “axially-tensioning method”, which is used with electrical machines, e.g., a motor vehicle generator, a reliable axial position of the stator relative to the end shields of the generator must be attained, and the stator must be centered exactly relative to the rotor located in the stator. A centering surface on an outer circumference of the laminated core makes it possible to locate the stator extremely exactly in the end shields, and to assign the stator to the rotor extremely exactly.
Methods for manufacturing a radial centering surface of this type are known from the related art. Unexamined patent application DT 23 44 193 A1 discloses a method, with which the centering surface is created via plastic deformation. When the stamping tool used is opened, individual laminations of the laminated core or regions thereof remain stuck on the tool and are pulled off of the laminated core. The centering surface is damaged via the bent laminations, and the stator is no longer installable. Since the damage occurs at the end of the value chain, the waste costs are high.
Publication WO 2004/030185 makes known a chip-removing machining method that involves truing a centering surface. It may happen that one or more laminations become detached from the laminated core due to the high radial load.